Uridine diphosphate glucuronic acid production and utilization in various tissues actively synthesizing glycosaminoglycans

Abstract

1. UDP-glucose dehydrogenase has been partially purified from sheep nasal septum cartilage, neonatal rat skin and bovine corneal epithelium. 2. The pH profile, Km values for NAD+ and UDP-glucose, activation energy and molecular weight have been determined for the enzyme from several of the tissues. 3. The sugar nucleotide concentrations in each of the tissues have been related to the spectrum of glycosaminoglycans produced by each tissue. 4. The presence of an allosteric UDP-xylose-binding site distinct from the active site(s) in sheep nasal septum UDP-glucose dehydrogenase has been demonstrated. 5. An active UDP-glucuronic acid nucleotidase has been demonstrated in sheep nasal cartilage. 6. Tissue-space experiments have shown the cell water content of sheep nasal septum cartilage to be 14% of the wet weight. 7. Glucuronic acid 1-phosphate does not occur in measurable amounts in sheep nasal septum cartilage and no UDP-glucuronic acid pyrophosphorylase activity could be detected in this tissue. 8. The inhibition by UDP-xylose with respect to both substrates, UDP-glucose and NAD+, has been examined, and shown to be allosteric.